A Step by Step Guide to Making Your Own Maple Syrup
If you find a healthy maple tree (not too young, or too dried up, and preferably in an old growth forest), it can share with you a gallon of sap a day (containing 1-2% sugar and a lot of minerals), which can be boiled down to maple syrup (60%+ sugar content. Once you make and taste your own maple syrup, you would not want to buy the store brands anymore (even the pure maple syrup, let alone the high fructose types mislabeled as maple syrup). The following article explains some little-known tricks to make your own maple syrup. Like everything else good in life and nature, you need patience and time (taken away from money making!) and patience, for which you will be rewarded with joy, wisdom, health, peace and contentment.
The Sap
Maple syrup is created by a lengthy process that concentrates the natural sugars in maple sap. Trees use sap, like humans use blood, to feed their branches, leaves and roots with natural simple sugars and minerals. The maple tree most commonly tapped in syrup production, the sugar maple, Acer Saccharum, is a tree native to the eastern half of North America, growing as a large and stately tree in woods and open meadows, having gray bark and 5-lobed leaves. In states such as Vermont and New Hampshire, the sugar maple is sometimes the only tree found in some forests, forming dense groves of large trees. It provides a beautiful and colorful display of gold, red, and orange colors in autumn. The sugar maple grows very well in cold, rocky, and steep areas, so it is a common sight in most regions of the Appalachian mountain range. Its presence is much more common in the higher and colder regions of eastern North America than in the warmer lowlands by the ocean. Sugar maples are hardy and versatile. They can be found growing in dark forest canopies as understory trees as well as in open sunny meadows. Large-scale commercial syrup producers mainly base their operations in the New England states and in Canada, where healthy maple groves are common and close in proximity. Proper access to the location of the maple grove is also essential, as difficult locations can hinder worker access to maples, such as in very steep and rocky areas.
In warmer seasons, a large sugar maple tree with its crown at the top of the forest canopy might move (due to photosynthetic-induced transpiration and diffusive root pressures) around 200 liters of water from the roots to the evaporating surfaces of leaves, 30 meters above the forest floor. Mineral nutrients from the soil, along with sugar and hormones and other physiological constituents manufactured or stored in the roots or stems sometimes also rise dissolved in the water and collectively form the sap. The sap ascends from root to leaf in the xylem made of vascular tracheary elements (shown in the picture).
Maple sap flow during the leafless season is physiologically unique in that it is largely independent of root pressure and only occurs on occasions between October and April when warm days follow freezing nights. Maple winter sap flow is caused by pressure in the stem generated by alternating daily cycles of night freezes and warm days. Cool evening temperatures generate negative pressure from the dissolution of gases in the xylem, which were seeded in from adjacent parenchyma and intercellular spaces. The negative pressure replicates the effect of transpiration, which draws still-liquid water from the soil into the roots. As the night freeze deepens, water freezes along the inner walls of the hollow fiber cells adjacent to the xylem and in intercellular spaces. Eventually vaporized water on the surfaces of all cells freezes. The ice formation compresses and traps gases in the stem. The heat of the day melts the ice and causes expansion of the compressed gases, which generates positive pressure in the stem that pushes the sap up the stem and out the nearest exit, if one exists, such as a maple producer’s spile. Applying vacuum pressure to the tap allows a maple producer to collect up to three times the normal amount of sap, and doing so has been the industry standard since the late sixties although for our own home use, we don’t like to apply vacuum or insert multiple tapping points on our trees. Our small tapping points are no different than a bird poking a small hole on the tree trunk and will heal in about 6 weeks. We don’t use synthetic chemicals to seal the tapping holes. We also don’t tap thin young small trees (less than 12” in diameter) or older trees that seem unhealthy.
The sugar in the sap stream is mobilized in late winter and exuded into the xylem sapstream to fuel flowering and leaf expansion (maples flower before they leaf out). Most of the carbohydrates in the rays are actually stored as starch grains, and an enzyme released into the xylem throughout late winter converts the starch to sucrose and mobilizes it in the xylem. Sap sugar content also varies within a sap flow season, peaking in the middle. Therefore, there is quite an art to the timing of the tree tap. Producers should tap right before the peak sugar content sap flows. If they tap too early, the tap site might dry out, and they will collect mostly lower sugar content sap. We wait until daily freeze-thaw temperature cycles fluctuate +/- 10 to 15 degree Fahrenheit above and below the freezing point (of 32 degrees), that create enough pressure and flow in the sap channels. In our area in Pennsylvania, this usually happens in early February, which signal the beginning of tapping season. The larger the temperature difference between the night freeze and the daily thaw and greater the number of days in a season with big freeze-thaw cycles, the greater will be the volume of sap collected.
Maple syrup is mostly sucrose, but the maple xylem sap stream also contains glucose, inorganic salts (a lot of manganese and zinc and some magnesium, calcium, potassium), protein precursors (peptides and amino acids), riboflavin (Vitamin B21), some enzymes, minerals and a few mystery organic compounds. The sugar content question is economically critical. If a sugar maple canopy sees enough sun and has enough water and nutrients in a summer to photosynthesize more sugar than it needs, it would store it for higher sugar-content sap in the Winter. Generally speaking, shade-tolerant trees seem to always expect to have all or part of their future canopy shaded, so they save sugar to survive the lean times.
To make syrup, sap is boiled down until it is about 67% sugar. This means that if the sap has 2% sugar, as is typical for sugar maples, it takes 44 gallons of sap to make one gallon of syrup (the formula is 88.2 divided by initial sap sugar content, in percent). The darker color and more robust flavor of Grade B maple syrups indicate lower sugar content (say 1%) in the sap. More boiling means more heat and darker color. Fermentation happens in syrups with less than 50% sugar content. We sometimes stop our boiling (see below) at 50% sugar content and refrigerate the thin syrup for use within a few weeks (before extensive fermentation occurs). Unlike our home-made syrup (for our own use), many large-scale commercial syrup producers run their sap through a reverse osmosis machine to remove some of the water from the sap to concentrate the solution before the boiling begins, so that less time and fuel will be necessary to reach the syrup stage.
Tapping and Collecting Sap
Now we share the process we use to collect and boil our sap….
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